List<int> list = new List<int>();        list.Add(1);        list.Add(2);                list.Add(3);        Cache["Key"] = list;        var list2 = Cache["Key"] as List<int>;        List<int> listNew = list2;        listNew.Add(4);        if (list2 != null && list2.Count > 0)        {            foreach (int i in list2)            {                Response.Write(i + "<br/>");            }        }
结果1234